Speaker units are used in portable information terminals such as mobile phone, DSC (Digital Still Camera), PDA (Personal Digital Assistant), and PC (Personal Computer). A speaker unit herein includes a so-called speaker and a receiver.
An electroacoustic transducer (speaker unit) has been proposed that has a flat-shaped coil (horizontal coil) wound in such a manner that the number of coil layers in the width direction is larger than the number of coil layers in the thickness direction so as to reduce the size and the thickness (see for example Japanese Patent No. 3213521: Patent Document 1).    Patent Document 1: Japanese Patent No. 3213521